Low-pressure H2/N2 annealing on indium tin oxide film

Annealing of indium tin oxide (ITO) film in low-pressure H2/N2 was investigated. On carefully selecting the annealing process window, apparent electrical property improvement as well as good optical property can be obtained. It was found that ITO annealed with 2 Pa, H2/N2:6/6 sccm, at 500 °C for an hour can increase its electrical conductivity 60% more than ITO without annealing, 58% more than ITO annealed with pure H2. An annealed ITO without specially selected recipe can easily possess worse electrical and optical properties than that without annealing. It can be explained that annealing ITO in a hydrogen-contained environment can lead to hydrogen reduction–oxygen vacancy playing a donor role in ITO; however, annealing also provides the energy to remove ITO material defects including donors.